1 /* 2 * Copyright (c) 1999, 2023, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "c1/c1_MacroAssembler.hpp" 27 #include "c1/c1_Runtime1.hpp" 28 #include "compiler/compilerDefinitions.inline.hpp" 29 #include "gc/shared/barrierSet.hpp" 30 #include "gc/shared/barrierSetAssembler.hpp" 31 #include "gc/shared/collectedHeap.hpp" 32 #include "gc/shared/tlab_globals.hpp" 33 #include "interpreter/interpreter.hpp" 34 #include "oops/arrayOop.hpp" 35 #include "oops/markWord.hpp" 36 #include "runtime/basicLock.hpp" 37 #include "runtime/os.hpp" 38 #include "runtime/sharedRuntime.hpp" 39 #include "runtime/stubRoutines.hpp" 40 41 int C1_MacroAssembler::lock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 42 const int aligned_mask = BytesPerWord -1; 43 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 44 assert(hdr == rax, "hdr must be rax, for the cmpxchg instruction"); 45 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 46 Label done; 47 int null_check_offset = -1; 48 49 verify_oop(obj); 50 51 // save object being locked into the BasicObjectLock 52 movptr(Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes()), obj); 53 54 null_check_offset = offset(); 55 56 if (DiagnoseSyncOnValueBasedClasses != 0) { 57 load_klass(hdr, obj, rscratch1); 58 movl(hdr, Address(hdr, Klass::access_flags_offset())); 59 testl(hdr, JVM_ACC_IS_VALUE_BASED_CLASS); 60 jcc(Assembler::notZero, slow_case); 61 } 62 63 // Load object header 64 movptr(hdr, Address(obj, hdr_offset)); 65 // and mark it as unlocked 66 orptr(hdr, markWord::unlocked_value); 67 // save unlocked object header into the displaced header location on the stack 68 movptr(Address(disp_hdr, 0), hdr); 69 // test if object header is still the same (i.e. unlocked), and if so, store the 70 // displaced header address in the object header - if it is not the same, get the 71 // object header instead 72 MacroAssembler::lock(); // must be immediately before cmpxchg! 73 cmpxchgptr(disp_hdr, Address(obj, hdr_offset)); 74 // if the object header was the same, we're done 75 jcc(Assembler::equal, done); 76 // if the object header was not the same, it is now in the hdr register 77 // => test if it is a stack pointer into the same stack (recursive locking), i.e.: 78 // 79 // 1) (hdr & aligned_mask) == 0 80 // 2) rsp <= hdr 81 // 3) hdr <= rsp + page_size 82 // 83 // these 3 tests can be done by evaluating the following expression: 84 // 85 // (hdr - rsp) & (aligned_mask - page_size) 86 // 87 // assuming both the stack pointer and page_size have their least 88 // significant 2 bits cleared and page_size is a power of 2 89 subptr(hdr, rsp); 90 andptr(hdr, aligned_mask - (int)os::vm_page_size()); 91 // for recursive locking, the result is zero => save it in the displaced header 92 // location (NULL in the displaced hdr location indicates recursive locking) 93 movptr(Address(disp_hdr, 0), hdr); 94 // otherwise we don't care about the result and handle locking via runtime call 95 jcc(Assembler::notZero, slow_case); 96 // done 97 bind(done); 98 99 inc_held_monitor_count(); 100 101 return null_check_offset; 102 } 103 104 void C1_MacroAssembler::unlock_object(Register hdr, Register obj, Register disp_hdr, Label& slow_case) { 105 const int aligned_mask = BytesPerWord -1; 106 const int hdr_offset = oopDesc::mark_offset_in_bytes(); 107 assert(disp_hdr == rax, "disp_hdr must be rax, for the cmpxchg instruction"); 108 assert(hdr != obj && hdr != disp_hdr && obj != disp_hdr, "registers must be different"); 109 Label done; 110 111 // load displaced header 112 movptr(hdr, Address(disp_hdr, 0)); 113 // if the loaded hdr is NULL we had recursive locking 114 testptr(hdr, hdr); 115 // if we had recursive locking, we are done 116 jcc(Assembler::zero, done); 117 // load object 118 movptr(obj, Address(disp_hdr, BasicObjectLock::obj_offset_in_bytes())); 119 120 verify_oop(obj); 121 // test if object header is pointing to the displaced header, and if so, restore 122 // the displaced header in the object - if the object header is not pointing to 123 // the displaced header, get the object header instead 124 MacroAssembler::lock(); // must be immediately before cmpxchg! 125 cmpxchgptr(hdr, Address(obj, hdr_offset)); 126 // if the object header was not pointing to the displaced header, 127 // we do unlocking via runtime call 128 jcc(Assembler::notEqual, slow_case); 129 // done 130 bind(done); 131 132 dec_held_monitor_count(); 133 } 134 135 136 // Defines obj, preserves var_size_in_bytes 137 void C1_MacroAssembler::try_allocate(Register obj, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, Label& slow_case) { 138 if (UseTLAB) { 139 tlab_allocate(noreg, obj, var_size_in_bytes, con_size_in_bytes, t1, t2, slow_case); 140 } else { 141 jmp(slow_case); 142 } 143 } 144 145 146 void C1_MacroAssembler::initialize_header(Register obj, Register klass, Register len, Register t1, Register t2) { 147 assert_different_registers(obj, klass, len); 148 movptr(Address(obj, oopDesc::mark_offset_in_bytes()), checked_cast<int32_t>(markWord::prototype().value())); 149 #ifdef _LP64 150 if (UseCompressedClassPointers) { // Take care not to kill klass 151 movptr(t1, klass); 152 encode_klass_not_null(t1, rscratch1); 153 movl(Address(obj, oopDesc::klass_offset_in_bytes()), t1); 154 } else 155 #endif 156 { 157 movptr(Address(obj, oopDesc::klass_offset_in_bytes()), klass); 158 } 159 160 if (len->is_valid()) { 161 movl(Address(obj, arrayOopDesc::length_offset_in_bytes()), len); 162 } 163 #ifdef _LP64 164 else if (UseCompressedClassPointers) { 165 xorptr(t1, t1); 166 store_klass_gap(obj, t1); 167 } 168 #endif 169 } 170 171 172 // preserves obj, destroys len_in_bytes 173 void C1_MacroAssembler::initialize_body(Register obj, Register len_in_bytes, int hdr_size_in_bytes, Register t1) { 174 assert(hdr_size_in_bytes >= 0, "header size must be positive or 0"); 175 Label done; 176 177 // len_in_bytes is positive and ptr sized 178 subptr(len_in_bytes, hdr_size_in_bytes); 179 zero_memory(obj, len_in_bytes, hdr_size_in_bytes, t1); 180 bind(done); 181 } 182 183 184 void C1_MacroAssembler::allocate_object(Register obj, Register t1, Register t2, int header_size, int object_size, Register klass, Label& slow_case) { 185 assert(obj == rax, "obj must be in rax, for cmpxchg"); 186 assert_different_registers(obj, t1, t2); // XXX really? 187 assert(header_size >= 0 && object_size >= header_size, "illegal sizes"); 188 189 try_allocate(obj, noreg, object_size * BytesPerWord, t1, t2, slow_case); 190 191 initialize_object(obj, klass, noreg, object_size * HeapWordSize, t1, t2, UseTLAB); 192 } 193 194 void C1_MacroAssembler::initialize_object(Register obj, Register klass, Register var_size_in_bytes, int con_size_in_bytes, Register t1, Register t2, bool is_tlab_allocated) { 195 assert((con_size_in_bytes & MinObjAlignmentInBytesMask) == 0, 196 "con_size_in_bytes is not multiple of alignment"); 197 const int hdr_size_in_bytes = instanceOopDesc::header_size() * HeapWordSize; 198 199 initialize_header(obj, klass, noreg, t1, t2); 200 201 if (!(UseTLAB && ZeroTLAB && is_tlab_allocated)) { 202 // clear rest of allocated space 203 const Register t1_zero = t1; 204 const Register index = t2; 205 const int threshold = 6 * BytesPerWord; // approximate break even point for code size (see comments below) 206 if (var_size_in_bytes != noreg) { 207 mov(index, var_size_in_bytes); 208 initialize_body(obj, index, hdr_size_in_bytes, t1_zero); 209 } else if (con_size_in_bytes <= threshold) { 210 // use explicit null stores 211 // code size = 2 + 3*n bytes (n = number of fields to clear) 212 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 213 for (int i = hdr_size_in_bytes; i < con_size_in_bytes; i += BytesPerWord) 214 movptr(Address(obj, i), t1_zero); 215 } else if (con_size_in_bytes > hdr_size_in_bytes) { 216 // use loop to null out the fields 217 // code size = 16 bytes for even n (n = number of fields to clear) 218 // initialize last object field first if odd number of fields 219 xorptr(t1_zero, t1_zero); // use t1_zero reg to clear memory (shorter code) 220 movptr(index, (con_size_in_bytes - hdr_size_in_bytes) >> 3); 221 // initialize last object field if constant size is odd 222 if (((con_size_in_bytes - hdr_size_in_bytes) & 4) != 0) 223 movptr(Address(obj, con_size_in_bytes - (1*BytesPerWord)), t1_zero); 224 // initialize remaining object fields: rdx is a multiple of 2 225 { Label loop; 226 bind(loop); 227 movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (1*BytesPerWord)), 228 t1_zero); 229 NOT_LP64(movptr(Address(obj, index, Address::times_8, hdr_size_in_bytes - (2*BytesPerWord)), 230 t1_zero);) 231 decrement(index); 232 jcc(Assembler::notZero, loop); 233 } 234 } 235 } 236 237 if (CURRENT_ENV->dtrace_alloc_probes()) { 238 assert(obj == rax, "must be"); 239 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 240 } 241 242 verify_oop(obj); 243 } 244 245 void C1_MacroAssembler::allocate_array(Register obj, Register len, Register t1, Register t2, int header_size, Address::ScaleFactor f, Register klass, Label& slow_case) { 246 assert(obj == rax, "obj must be in rax, for cmpxchg"); 247 assert_different_registers(obj, len, t1, t2, klass); 248 249 // determine alignment mask 250 assert(!(BytesPerWord & 1), "must be a multiple of 2 for masking code to work"); 251 252 // check for negative or excessive length 253 cmpptr(len, checked_cast<int32_t>(max_array_allocation_length)); 254 jcc(Assembler::above, slow_case); 255 256 const Register arr_size = t2; // okay to be the same 257 // align object end 258 movptr(arr_size, header_size * BytesPerWord + MinObjAlignmentInBytesMask); 259 lea(arr_size, Address(arr_size, len, f)); 260 andptr(arr_size, ~MinObjAlignmentInBytesMask); 261 262 try_allocate(obj, arr_size, 0, t1, t2, slow_case); 263 264 initialize_header(obj, klass, len, t1, t2); 265 266 // clear rest of allocated space 267 const Register len_zero = len; 268 initialize_body(obj, arr_size, header_size * BytesPerWord, len_zero); 269 270 if (CURRENT_ENV->dtrace_alloc_probes()) { 271 assert(obj == rax, "must be"); 272 call(RuntimeAddress(Runtime1::entry_for(Runtime1::dtrace_object_alloc_id))); 273 } 274 275 verify_oop(obj); 276 } 277 278 279 280 void C1_MacroAssembler::inline_cache_check(Register receiver, Register iCache) { 281 verify_oop(receiver); 282 // explicit NULL check not needed since load from [klass_offset] causes a trap 283 // check against inline cache 284 assert(!MacroAssembler::needs_explicit_null_check(oopDesc::klass_offset_in_bytes()), "must add explicit null check"); 285 int start_offset = offset(); 286 287 if (UseCompressedClassPointers) { 288 load_klass(rscratch1, receiver, rscratch2); 289 cmpptr(rscratch1, iCache); 290 } else { 291 cmpptr(iCache, Address(receiver, oopDesc::klass_offset_in_bytes())); 292 } 293 // if icache check fails, then jump to runtime routine 294 // Note: RECEIVER must still contain the receiver! 295 jump_cc(Assembler::notEqual, 296 RuntimeAddress(SharedRuntime::get_ic_miss_stub())); 297 const int ic_cmp_size = LP64_ONLY(10) NOT_LP64(9); 298 assert(UseCompressedClassPointers || offset() - start_offset == ic_cmp_size, "check alignment in emit_method_entry"); 299 } 300 301 302 void C1_MacroAssembler::build_frame(int frame_size_in_bytes, int bang_size_in_bytes) { 303 assert(bang_size_in_bytes >= frame_size_in_bytes, "stack bang size incorrect"); 304 // Make sure there is enough stack space for this method's activation. 305 // Note that we do this before doing an enter(). This matches the 306 // ordering of C2's stack overflow check / rsp decrement and allows 307 // the SharedRuntime stack overflow handling to be consistent 308 // between the two compilers. 309 generate_stack_overflow_check(bang_size_in_bytes); 310 311 push(rbp); 312 if (PreserveFramePointer) { 313 mov(rbp, rsp); 314 } 315 #if !defined(_LP64) && defined(COMPILER2) 316 if (UseSSE < 2 && !CompilerConfig::is_c1_only_no_jvmci()) { 317 // c2 leaves fpu stack dirty. Clean it on entry 318 empty_FPU_stack(); 319 } 320 #endif // !_LP64 && COMPILER2 321 decrement(rsp, frame_size_in_bytes); // does not emit code for frame_size == 0 322 323 BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler(); 324 // C1 code is not hot enough to micro optimize the nmethod entry barrier with an out-of-line stub 325 bs->nmethod_entry_barrier(this, NULL /* slow_path */, NULL /* continuation */); 326 } 327 328 329 void C1_MacroAssembler::remove_frame(int frame_size_in_bytes) { 330 increment(rsp, frame_size_in_bytes); // Does not emit code for frame_size == 0 331 pop(rbp); 332 } 333 334 335 void C1_MacroAssembler::verified_entry(bool breakAtEntry) { 336 if (breakAtEntry || VerifyFPU) { 337 // Verified Entry first instruction should be 5 bytes long for correct 338 // patching by patch_verified_entry(). 339 // 340 // Breakpoint and VerifyFPU have one byte first instruction. 341 // Also first instruction will be one byte "push(rbp)" if stack banging 342 // code is not generated (see build_frame() above). 343 // For all these cases generate long instruction first. 344 fat_nop(); 345 } 346 if (breakAtEntry) int3(); 347 // build frame 348 IA32_ONLY( verify_FPU(0, "method_entry"); ) 349 } 350 351 void C1_MacroAssembler::load_parameter(int offset_in_words, Register reg) { 352 // rbp, + 0: link 353 // + 1: return address 354 // + 2: argument with offset 0 355 // + 3: argument with offset 1 356 // + 4: ... 357 358 movptr(reg, Address(rbp, (offset_in_words + 2) * BytesPerWord)); 359 } 360 361 #ifndef PRODUCT 362 363 void C1_MacroAssembler::verify_stack_oop(int stack_offset) { 364 if (!VerifyOops) return; 365 verify_oop_addr(Address(rsp, stack_offset)); 366 } 367 368 void C1_MacroAssembler::verify_not_null_oop(Register r) { 369 if (!VerifyOops) return; 370 Label not_null; 371 testptr(r, r); 372 jcc(Assembler::notZero, not_null); 373 stop("non-null oop required"); 374 bind(not_null); 375 verify_oop(r); 376 } 377 378 void C1_MacroAssembler::invalidate_registers(bool inv_rax, bool inv_rbx, bool inv_rcx, bool inv_rdx, bool inv_rsi, bool inv_rdi) { 379 #ifdef ASSERT 380 if (inv_rax) movptr(rax, 0xDEAD); 381 if (inv_rbx) movptr(rbx, 0xDEAD); 382 if (inv_rcx) movptr(rcx, 0xDEAD); 383 if (inv_rdx) movptr(rdx, 0xDEAD); 384 if (inv_rsi) movptr(rsi, 0xDEAD); 385 if (inv_rdi) movptr(rdi, 0xDEAD); 386 #endif 387 } 388 389 #endif // ifndef PRODUCT